Apparatus and method for surface treatment of cylindrical elements

ABSTRACT

The invention relates to a device ( 10 ) for treating surfaces of cylindrical elements in several process steps, including a first cleaning device ( 30 ) for removing residuals of a coolant and lubricant used during draw wall ironing from a cylindrical element produced through draw wall ironing so that a cleaned and pre-dried cylindrical element is provided. The device includes a surface treatment device ( 50 ) for treating at least one surface of the cleaned and pre dried cylindrical element and a second cleaning device ( 70 ) for cleaning the surface treated cylindrical element.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC §119 to German PatentApplication No. 10 201 2 201815.8 filed on Feb. 7, 2012, whichapplication is hereby incorporated by reference.

TECHNICAL FIELD

The invention relates to a device and a method for surface treatment ofcylindrical elements through draw wall ironing.

BACKGROUND OF THE INVENTION

A process designated as draw wall ironing produces a cylindrical elementfor example in the production of beverage cans from a bowl that isgenerally produced from sheet metal through deep drawing, wherein thebowl essentially has the dimensions of the final product to be producedbesides still requiring trimming and necking.

Draw wall ironing reduces a wall thickness and the exterior dimension ofthe bowl to form the cylindrical element. For process reasons the drawwall ironing is performed “wet” which is different from impact extrudingand uses a cooling- and lubricating agent.

During conventional processing a trimming of the free sheet metal edgeand a complex cleaning and drying of the produced cylindrical element isperformed subsequent to draw wall ironing.

SUMMARY OF THE INVENTION

Thus, it is an object of the present invention to provide a device and amethod for surface treatment of cylindrical elements in the context ofdraw wall ironing, wherein the device facilitates at least oneadditional variant of surface treatment without additional complexity.

In order to achieve the element a device for surface treatment ofcylindrical elements with a surface treatment in several process stepsis proposed including a first cleaning device for removing residuals ofa coolant and lubricant used for draw wall ironing from a cylindricalelement produced through draw wall ironing so that a cleaned and predried cylindrical element is provided, a surface treatment device fortreating at least one surface of the cleaned and pre dried cylindricalelement and a second cleaning device for cleaning the surface treatedcylindrical element.

Typically a surface treatment method like for example brushing is beingavoided if possible in known production methods which use draw wallironing since such processing generates a sludge from the releasedmaterial and the cooling and lubricating agents, which sludge is onlyremovable with great difficulty and which necessitates an immediate andcomplex cleaning of the processing machines since otherwise a failure ofthe machines would have to be expected soon thereafter. A surfacetreatment like for example brushing could also be performed aftercomplete cleaning and drying of the cylindrical element essentially atan end of the conventional process before optional painting, whereinrenewed cleaning would be possible before painting or similar finishing.

The invention provides the advantage that it avoids the complex cleaningthat was customary so far with little additional complexity or at leastsubstantially reduces the associated complexity.

A method for surface treatment of cylindrical elements is also proposed,including the following steps: providing a cylindrical element that isproduced through draw wall ironing, removing the residuals of a cooling-and lubricating agent used for draw wall ironing from the cylindricalelement, so that a cleaned and pre-dried cylindrical element isprovided, treating at least one surface of the cleaned and pre-driedcylindrical element and cleaning the surface treated cylindricalelement.

Additionally a computer program is proposed that includes computerprogram devices which cause a computer to control a device according tothe invention to execute the method according to the invention when thecomputer program is executed on the computer.

The invention is based on the finding that it is sufficient for avoidingor reducing the problems recited supra to combine a partial cleaning (inthe sense of a non-final cleaning) with a subsequent rudimentary dryingprocess in order to provide a desired surface treatment. It can bestated that the surface treatment with preceding limited drying isinserted between a first and a second portion of a known two stepwashing method. However, it is appreciated that the first and the secondcleaning device are not limited to only performing respective partialsteps of a conventional washing process. It is possible that processeswhich are performed by the first and the second cleaning device overlapwith one another, thus particular method steps are performed twice.

The invention requires an additional drying device in a practicalapplication in addition to the surface treatment device compared to aconventional process, wherein the additional drying device, however,only has to comply with reduced requirements and overall requires moreinstallation space. The advantages associated with avoiding or at leastreducing the problems recited supra, however, justify this comparativelysmall increase in complexity.

In order to simplify the language, the instant application recites acooling- and lubrication agent in conjunction with draw wall ironing. Itis appreciated that this initially does not have to be a homogenous orsingle substance agent since a mix of different agents (i.e. liquids)can be used. The term “cooling and lubrication agent” furthermore doesnot have to be interpreted in every case in a limited manner so that theagent is simultaneously used for cooling and lubrication purposes. Theterm “cooling and lubrication agent” eventually stands for the meanswhich are used for supporting or simplifying the process of draw wallironing or a process like deep drawing a bowl as an intermediary productwhich may be performed before the draw wall ironing.

In this application the term “cylindrical element” initially designatesa beaker shaped element with a base and a sidewall, wherein thecross-section is circular. The application, however, is not limited tosuch configuration. It is also possible in the context of the presentinvention that the cylindrical element is either initially producedwithout a base or that the base is removed during the process.Deviations from the circular cross-section of the wall are not excludedas a matter of principle either. It is furthermore appreciated that thebase does not have to be flat and can have some shaping.

In an advantageous embodiment, the surface processing device isconfigured for roughening or optically matting the at least one surface,preferably for brushing the at least one surface.

The use of brushing for surface treatment is known for example in acontext with cans generated through flow pressing, wherein an occurrenceof abrasion in a context with “wet” draw wall ironing and the “sludge”associated therewith thus made brushing after draw wall ironingunattractive for process technology reasons so far. In the context ofthe present invention, however, brushing can be used largelycircumventing a sludge formation after draw wall ironing.

Thus, the present invention is not limited to brushing. For example alaser treatment or a plasma treatment can also be used as alternativeand/or supplemental methods.

In an advantageous embodiment the device furthermore includes anabrasion removal device for preferably dry removal of abrasion that hasbeen generated during surface processing from the cylindrical element,in particular through an air flow or an air blast before cleaning thesurface treated cylindrical element.

Due to the pre drying performed before the surface treatment, theabrasion generated during processing also remains in a dry state whichfacilitates a simple removal, for example through air impact. It isappreciated that the removal can also be performed using another gas orgas mix.

In an advantageous embodiment, the first cleaning device includes apre-washing unit for removing residuals of the cooling- and lubricationagent and a drying device for drying the cylindrical element which hasbeen cleaned from the cooling and lubricating agent.

For example when the cooling and lubricating agent includes light soapsand oils, these can be removed with a respectively adapted pre-washingunit, wherein a drying comes after this removal. The agents used forpre-washing can be preferably removed in a simpler manner from thesurface for drying than this would be the case for the cooling- andlubricating agents themselves.

In an advantageous embodiment, the pre-washing unit is configured foretching the cylindrical element, in particular through acid treatmentand/or a base treatment.

The “washing” of the cylindrical elements known from the conventionalmethod sometimes includes etching with an acid and/or a base, whereinfor example an acid treatment can be performed by the pre-washing unit.

It is furthermore possible in the first and second cleaning device toprovide different treatments, for example a treatment with an acid and atreatment with a base in different cleaning devices in order to betterseparate the different treatments from one another.

In an advantageous embodiment the drying device is configured for dryingat least the surface provided for surface treatment up to a first degreeof drying, preferably up to a second degree of drying, wherein noadditional droplets form at least at the surface provided for surfacetreatment and wherein the second degree of drying is characterized inthat no humidity is sucked into a downstream vacuum system.

A complete drying of the surface that is typically provided forpreparing a lacquering or coating is not required for preparing thesurface treatment. It has been found that generally already a firstdegree of drying is sufficient for significantly reducing the problemsinitially stated wherein no drops are formed anymore at the cylindricalelement. A stronger drying could mean for example for a second degree ofdrying that also in a hypothetical subsequent vacuum system no wetnessor only insignificant wetness is sucked in. A third degree of dryingrepresents a level of dryness in which removed particles, thus abrasiondo not adhere to one another anymore due to van-der-Waals-forces.

In the practical implementation a balance adapted to particularconditions can be found between the desired or required degree ofdryness and a simpler abrasion removal associated therewith and thecomplexity to achieve this degree of drying.

In an advantageous embodiment, the drying unit includes an oven and/or ablower for drying.

The drying unit can thus provide drying through a combination of an air-or gas-flow and an oven impact (e.g. convection, radiation and/orinduction) or also only singular means.

In an advantageous embodiment, the cylindrical element is a one-pieceelement that is closed at its base and made from aluminum or an aluminumalloy.

Even though the invention is not limited to a cylindrical element with abase made from aluminum or an aluminum alloy, this constellationrepresents a preferred implementation.

Alternatively it is however also possible for example to provide acylindrical element made from steel sheet metal or tin plated steelsheet metal, in particular to provide a surface treatment through laserand/or plasma processing. A brushing of tin plated steel sheet metal mayonly be performed up to a depth in which it remains assured that the tinis not removed from the surface.

In an advantageous embodiment the second cleaning device is configuredfor washing and drying the surface treated cylindrical element, inparticular for washing and drying to prepare a further processing of thecylindrical element.

Through dividing the cleaning steps in a first and second cleaningdevice, it is possible to pull the cleaning steps ahead which arerequired or desired for preparing the surface treatment, wherein theremaining or eventually additional cleaning- or drying steps areprovided in a final step in the second cleaning device.

In an advantageous embodiment the second cleaning device is configuredfor a base treatment of the cylindrical element.

As stated supra providing the first and the second cleaning device canbe used to better separate different treatments from one another (e.g.acid treatment in the first cleaning device and base treatment in thesecond cleaning device). This way a protraction of employed agents thatcan occur in a conventional cleaning device can be avoided even better.

In an advantageous embodiment the device further includes a trimmingdevice for trimming the cylindrical element, wherein the trimming deviceis in particular configured for trimming the pre-dried cylindricalelement before surface treatment.

The trimming device for desired trimming of the cylindrical element canbe provided at different stages in the process, wherein preferably thetrimming is performed before the surface treatment.

In an advantageous embodiment, the device includes plural first cleaningdevices and/or plural surface treatment devices and/or plural secondcleaning devices which are respectively arranged for paralleloperations.

The particular process steps in the different elements of the device canuse different times per cylindrical element, wherein an optimum loadingof the entire process chain is achievable through respective operationof plural elements parallel to one another.

In an advantageous embodiment, the device includes a draw wall ironingdevice for producing a cylindrical element.

The invention can be used for a separate pre-fabrication and supplyingof cylindrical elements and also in a context where the cylindricalelements are produced directly before further processing them on site.This applies for producing a bowl, for example by deep drawing from apiece of sheet metal which precedes the draw wall ironing process.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is subsequently described based on embodiments withreference to appended drawing figures, wherein:

FIG. 1 illustrates an embodiment of a device according to the invention;and

FIG. 2 illustrates an embodiment of a method according to the invention.

DETAILED DESCRIPTION

FIG. 1 illustrates an embodiment of a device 10 according to theinvention. The device 10 includes a draw wall ironing device 20, a firstcleaning device 30, a trimming device 40, a surface treatment device 50,an abrasion removal device 60 and a second cleaning device 70.

The draw wall ironing device 20 is configured to receive a blank alsodesignated as bowl and to form a cylindrical element from the blankthrough draw wall ironing. The cylindrical element thus formed(sometimes also designated “pre form”) is supplied by the draw wallironing device 20 to the first cleaning device 30.

The first cleaning device 30 includes a pre-washing unit 32 and a dryingunit 34. Through the pre-washing unit residuals of cooling- andlubricating agent which was used during draw wall ironing are removedfrom the supplied cylindrical element, wherein this removing alsoincludes a treatment with an acid. The cylindrical element thussufficiently cleaned from cooling- and lubricating agent is then driedby the drying unit 34 which includes an oven and a blower (notillustrated) until a desired degree of drying is achieved in which nomore drops form at the dried cylindrical element. After running throughthe first drying unit 30, thus a cleaned and pre-dried cylindricalelement is provided which is provided to the trimming unit 40.

The trimming unit 40 is used to trim the cylindrical element to adesired dimension, wherein the trimming assures in particular thatdimensional deviations generated through the draw wall ironing withrespect to the height of the cylindrical element are removed. From thetrimming device 40 the trimmed cylindrical element is provided to thesurface processing unit 50.

Through the surface treatment device 50, a treatment in the form ofbrushing at least one of the surfaces of the cylindrical element isprovided so that the cylindrical element has a roughened and/oroptically more matt surface on the treated surface.

The abrasion particles released when brushing with the surface treatmentdevice 50 are removed by the abrasion removal device 60 in a dry mannerusing an air flow, wherein the cylindrical element thus cleaned fromabrasion is subsequently provided to the second cleaning device 70.

The second cleaning device 70, similar to the first cleaning device 30includes a washing unit 72 and a drying unit 74. Differently from thefirst cleaning device 30, however, the second cleaning device 70 isprovided for a final and complete cleaning of the cylindrical element,wherein in particular the drying unit 74 provides a molecular drying ofthe cylindrical element so that the eventually cleaned and driedcylindrical element can be coated and/or lacquered (not illustrated).

In the embodiment illustrated in FIG. 1, trimming with the trimmingdevice 40 is done before the surface treatment with the surfacetreatment device 50. It is appreciated that the process sequence is notmandatory and the trimming can be easily done after the surfacetreatment or at an earlier point in time (before the first cleaning) orat a later point in time.

Some process steps or devices which are designated as sequential in theembodiment, as this is the case during surface treatment in the surfacetreatment device 50 and abrasion removal in the abrasion removal device60, can also be performed in parallel or can be combined in a devicequite well. In a combined surface treatment and abrasion removal device,the abrasion released during surface treatment would also be removedsimultaneously.

It is furthermore possible that different devices of the deviceaccording to the invention jointly perform particular functions. Thus,for example abrasion removal can be performed up to a certain degreethrough the abrasion removal device 60, wherein the remaining residualabrasion is removed by the second cleaning device 70.

FIG. 2 illustrates an embodiment of a method according to the invention.The method includes providing 110 an element produced through draw wallironing, removing 120 of residuals of a coolant and lubricant usedduring draw wall ironing from the cylindrical element, so that a cleanedand pre-dried cylindrical element is provided, processing 130 at leastone surface of the cleaned and pre-dried cylindrical element andcleaning 140 the surface treated cylindrical element in this sequence.

The device 10 may include computer 80 in one or more of its associateddevices and units 20, 30, 32, 34, 40, 50, 60, 70, 72 and 74 or as aseparate computer, including a memory 82 stored with instructions, whichwhen executed by the computer, performs the method shown in FIG. 2.

REFERENCE NUMERALS AND DESIGNATIONS

10 device

20 draw wall ironing device

30 first cleaning device

32 pre-washing unit

34 drying unit

40 trimming device

50 surface treatment device

60 abrasion removal device

70 second cleaning device

72 washing unit

74 drying unit

80 computer

82 memory

110 providing

120 removing

130 treating

140 cleaning

What is claimed is:
 1. A device for treating surfaces of cylindricalelements in several process steps, comprising a first cleaning devicefor removing residuals of a coolant and lubricant used during draw wallironing from a cylindrical element produced through draw wall ironing sothat the cleaned and pre-dried cylindrical element is provided, and asurface treatment device for treating at least one surface of thecleaned and pre dried cylindrical element; and a second cleaning devicefor cleaning the surface treated cylindrical element.
 2. The deviceaccording to claim 1, wherein the surface treatment device is configuredfor roughening and/or optically matting the at least one surface,preferably for brushing the at least one surface.
 3. The deviceaccording to claim 1, further including an abrasion removal device forpreferably dry removal of abrasion generated during surface treatmentfrom the cylindrical element, in particular through an air flow or airblast before cleaning the cylindrical element.
 4. The device accordingto claim 1, wherein the first cleaning device includes a pre-washingdevice for removing of residuals of the coolant and lubricant and adrying unit for drying the cylindrical element that has been cleanedfrom the coolant and lubricant.
 5. The device according to claim 4,wherein the pre-washing unit is configured for etching the cylindricalelement, in particular through an acid treatment and/or a basetreatment.
 6. The device according to claim 4, wherein the drying unitis configured for drying at least the surface to be treated to a firstdegree of drying, preferably to a second degree of drying, wherein atleast no droplets form anymore at the surface provided for surfacetreatment in the first degree of drying, and wherein the second degreeof drying is characterized in that no moisture is sucked into asubsequent vacuum system.
 7. The device according to claim 4, whereinthe drying unit includes an oven and/or a blower for drying.
 8. Thedevice according to claim 1, wherein the cylindrical element is aone-piece element that is closed at its base and made from aluminum oran aluminum alloy.
 9. The device according to claim 1, wherein thesecond cleaning device is configured for washing and drying the surfacetreated cylindrical element, in particular for washing and drying toprepare a subsequent treatment of the cylindrical element.
 10. Thedevice according to claim 1, wherein the second cleaning device isconfigured for base treatment of the cylindrical element.
 11. The deviceaccording to claim 1, further including a trimming device for trimmingthe cylindrical element, wherein the trimming device is configured inparticular for trimming the cleaned and pre-dried cylindrical elementbefore surface treatment.
 12. The device according to claim 1, whereinthe device includes plural first cleaning devices and/or plural surfacetreatment devices and/or plural second cleaning devices respectivelyconfigured for parallel operations.
 13. The device according to claim 1,including a draw wall ironing device for producing the cylindricalelement.
 14. A method for surface treatment of cylindrical elements isalso proposed, comprising: providing a cylindrical element that isproduced through draw wall ironing; removing residuals of a coolant andlubricant from the cylindrical element, so that a cleaned and pre-driedcylindrical element is provided; treating at least one surface of thecleaned and pre-dried cylindrical element; and cleaning the surfacetreated cylindrical element.
 15. A computer including a memory storedwith instructions, which when executed by the computer cause a devicehaving a first cleaning device for removing residuals of a coolant andlubricant used during draw wall ironing from a cylindrical element, asurface treatment device for treating at least one surface of thecleaned and pre dried cylindrical element; and a second cleaning devicefor cleaning the surface treated cylindrical element, to: provide acylindrical element that is produced through draw wall ironing; removeresiduals of a coolant and lubricant from the cylindrical element, sothat a cleaned and pre-dried cylindrical element is provided; treat atleast one surface of the cleaned and pre-dried cylindrical element; andclean the surface treated cylindrical element.